summaryrefslogtreecommitdiff
path: root/src/expand.c
blob: 84d14d9246355844f64d768bc4fda6579d4ac905 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
/* expand - convert tabs to spaces
   Copyright (C) 89, 91, 1995-2002 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* By default, convert all tabs to spaces.
   Preserves backspace characters in the output; they decrement the
   column count for tab calculations.
   The default action is equivalent to -8.

   Options:
   --tabs=tab1[,tab2[,...]]
   -t tab1[,tab2[,...]]
   -tab1[,tab2[,...]]	If only one tab stop is given, set the tabs tab1
			spaces apart instead of the default 8.  Otherwise,
			set the tabs at columns tab1, tab2, etc. (numbered from
			0); replace any tabs beyond the tabstops given with
			single spaces.
   --initial
   -i			Only convert initial tabs on each line to spaces.

   David MacKenzie <djm@gnu.ai.mit.edu> */

#include <config.h>

#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>
#include "system.h"
#include "closeout.h"
#include "error.h"
#include "posixver.h"

/* The official name of this program (e.g., no `g' prefix).  */
#define PROGRAM_NAME "expand"

#define AUTHORS "David MacKenzie"

/* The number of bytes added at a time to the amount of memory
   allocated for the output line. */
#define OUTPUT_BLOCK 256

/* The number of bytes added at a time to the amount of memory
   allocated for the list of tabstops. */
#define TABLIST_BLOCK 256

/* The name this program was run with. */
char *program_name;

/* If nonzero, convert blanks even after nonblank characters have been
   read on the line. */
static int convert_entire_line;

/* If nonzero, the size of all tab stops.  If zero, use `tab_list' instead. */
static int tab_size;

/* Array of the explicit column numbers of the tab stops;
   after `tab_list' is exhausted, each additional tab is replaced
   by a space.  The first column is column 0. */
static int *tab_list;

/* The index of the first invalid element of `tab_list',
   where the next element can be added. */
static int first_free_tab;

/* Null-terminated array of input filenames. */
static char **file_list;

/* Default for `file_list' if no files are given on the command line. */
static char *stdin_argv[] =
{
  "-", NULL
};

/* Nonzero if we have ever read standard input. */
static int have_read_stdin;

/* Status to return to the system. */
static int exit_status;

static struct option const longopts[] =
{
  {"tabs", required_argument, NULL, 't'},
  {"initial", no_argument, NULL, 'i'},
  {GETOPT_HELP_OPTION_DECL},
  {GETOPT_VERSION_OPTION_DECL},
  {NULL, 0, NULL, 0}
};

void
usage (int status)
{
  if (status != 0)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
	     program_name);
  else
    {
      printf (_("\
Usage: %s [OPTION]... [FILE]...\n\
"),
	      program_name);
      fputs (_("\
Convert tabs in each FILE to spaces, writing to standard output.\n\
With no FILE, or when FILE is -, read standard input.\n\
\n\
"), stdout);
      fputs (_("\
Mandatory arguments to long options are mandatory for short options too.\n\
"), stdout);
      fputs (_("\
  -i, --initial       do not convert TABs after non whitespace\n\
  -t, --tabs=NUMBER   have tabs NUMBER characters apart, not 8\n\
"), stdout);
      fputs (_("\
  -t, --tabs=LIST     use comma separated list of explicit tab positions\n\
"), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    }
  exit (status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
}

/* Add tab stop TABVAL to the end of `tab_list', except
   if TABVAL is -1, do nothing. */

static void
add_tabstop (int tabval)
{
  if (tabval == -1)
    return;
  if (first_free_tab % TABLIST_BLOCK == 0)
    tab_list = (int *) xrealloc ((char *) tab_list,
				 (first_free_tab
				  + TABLIST_BLOCK * sizeof (tab_list[0])));
  tab_list[first_free_tab++] = tabval;
}

/* Add the comma or blank separated list of tabstops STOPS
   to the list of tabstops. */

static void
parse_tabstops (char *stops)
{
  int tabval = -1;

  for (; *stops; stops++)
    {
      if (*stops == ',' || ISBLANK (*stops))
	{
	  add_tabstop (tabval);
	  tabval = -1;
	}
      else if (ISDIGIT (*stops))
	{
	  if (tabval == -1)
	    tabval = 0;
	  tabval = tabval * 10 + *stops - '0';
	}
      else
	error (EXIT_FAILURE, 0, _("tab size contains an invalid character"));
    }

  add_tabstop (tabval);
}

/* Check that the list of tabstops TABS, with ENTRIES entries,
   contains only nonzero, ascending values. */

static void
validate_tabstops (int *tabs, int entries)
{
  int prev_tab = 0;
  int i;

  for (i = 0; i < entries; i++)
    {
      if (tabs[i] == 0)
	error (EXIT_FAILURE, 0, _("tab size cannot be 0"));
      if (tabs[i] <= prev_tab)
	error (EXIT_FAILURE, 0, _("tab sizes must be ascending"));
      prev_tab = tabs[i];
    }
}

/* Close the old stream pointer FP if it is non-NULL,
   and return a new one opened to read the next input file.
   Open a filename of `-' as the standard input.
   Return NULL if there are no more input files.  */

static FILE *
next_file (FILE *fp)
{
  static char *prev_file;
  char *file;

  if (fp)
    {
      if (ferror (fp))
	{
	  error (0, errno, "%s", prev_file);
	  exit_status = 1;
	}
      if (fp == stdin)
	clearerr (fp);		/* Also clear EOF. */
      else if (fclose (fp) == EOF)
	{
	  error (0, errno, "%s", prev_file);
	  exit_status = 1;
	}
    }

  while ((file = *file_list++) != NULL)
    {
      if (file[0] == '-' && file[1] == '\0')
	{
	  have_read_stdin = 1;
	  prev_file = file;
	  return stdin;
	}
      fp = fopen (file, "r");
      if (fp)
	{
	  prev_file = file;
	  return fp;
	}
      error (0, errno, "%s", file);
      exit_status = 1;
    }
  return NULL;
}

/* Change tabs to spaces, writing to stdout.
   Read each file in `file_list', in order. */

static void
expand (void)
{
  FILE *fp;			/* Input stream. */
  int c;			/* Each input character. */
  int tab_index = 0;		/* Index in `tab_list' of next tabstop. */
  int column = 0;		/* Column on screen of the next char. */
  int next_tab_column;		/* Column the next tab stop is on. */
  int convert = 1;		/* If nonzero, perform translations. */

  fp = next_file ((FILE *) NULL);
  if (fp == NULL)
    return;

  /* Binary I/O will preserve the original EOL style (DOS/Unix) of files.  */
  SET_BINARY2 (fileno (fp), STDOUT_FILENO);

  for (;;)
    {
      c = getc (fp);
      if (c == EOF)
	{
	  fp = next_file (fp);
	  if (fp == NULL)
	    break;		/* No more files. */
	  else
	    {
	      SET_BINARY2 (fileno (fp), STDOUT_FILENO);
	      continue;
	    }
	}

      if (c == '\n')
	{
	  putchar (c);
	  tab_index = 0;
	  column = 0;
	  convert = 1;
	}
      else if (c == '\t' && convert)
	{
	  if (tab_size == 0)
	    {
	      /* Do not let tab_index == first_free_tab;
		 stop when it is 1 less. */
	      while (tab_index < first_free_tab - 1
		     && column >= tab_list[tab_index])
		tab_index++;
	      next_tab_column = tab_list[tab_index];
	      if (tab_index < first_free_tab - 1)
		tab_index++;
	      if (column >= next_tab_column)
		next_tab_column = column + 1; /* Ran out of tab stops. */
	    }
	  else
	    {
	      next_tab_column = column + tab_size - column % tab_size;
	    }
	  while (column < next_tab_column)
	    {
	      putchar (' ');
	      ++column;
	    }
	}
      else
	{
	  if (convert)
	    {
	      if (c == '\b')
		{
		  if (column > 0)
		    --column;
		}
	      else
		{
		  ++column;
		  if (convert_entire_line == 0)
		    convert = 0;
		}
	    }
	  putchar (c);
	}
    }
}

int
main (int argc, char **argv)
{
  int tabval = -1;		/* Value of tabstop being read, or -1. */
  int c;			/* Option character. */

  bool obsolete_tablist = false;

  have_read_stdin = 0;
  exit_status = 0;
  convert_entire_line = 1;
  tab_list = NULL;
  first_free_tab = 0;
  program_name = argv[0];
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);

  atexit (close_stdout);

  while ((c = getopt_long (argc, argv, "it:,0123456789", longopts, NULL)) != -1)
    {
      switch (c)
	{
	case 0:
	  break;

	case '?':
	  usage (EXIT_FAILURE);
	case 'i':
	  convert_entire_line = 0;
	  break;
	case 't':
	  parse_tabstops (optarg);
	  break;
	case ',':
	  add_tabstop (tabval);
	  tabval = -1;
	  obsolete_tablist = true;
	  break;
	case_GETOPT_HELP_CHAR;
	case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
	default:
	  if (tabval == -1)
	    tabval = 0;
	  tabval = tabval * 10 + c - '0';
	  obsolete_tablist = true;
	  break;
	}
    }

  if (obsolete_tablist && 200112 <= posix2_version ())
    {
      error (0, 0, _("`-LIST' option is obsolete; use `-t LIST'"));
      usage (EXIT_FAILURE);
    }

  add_tabstop (tabval);

  validate_tabstops (tab_list, first_free_tab);

  if (first_free_tab == 0)
    tab_size = 8;
  else if (first_free_tab == 1)
    tab_size = tab_list[0];
  else
    tab_size = 0;

  if (optind == argc)
    file_list = stdin_argv;
  else
    file_list = &argv[optind];

  expand ();

  if (have_read_stdin && fclose (stdin) == EOF)
    error (EXIT_FAILURE, errno, "-");

  exit (exit_status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
}